SPECIES SUMMARY PAGE

Natrix natrix - Grass snake:

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Summary Information
Living Organisms / Animalia / Craniata / Reptilia / Squamata / Colubridae / Natrix / Species
Alternative Names
  • Ringed snake
  • Grass-snake
  • Natrix natrix helvetica
  • Tropidonotus natrix
  • Couleuvre a collier
  • Ringelnatter
Description Length:
  • Usually less than 12-cm, occasionally up to 200cm (B159, B160); females grow larger than males (B159)
  • Hatchlings: 16.0-19.0cm (B160)
  • One year old: 25.0-30.0cm (B160)

Appearance:

General description: Adults thick-bodied, head rounded and fairly well defined, dorsal scales are keeled, mid-body usually 19 rows of dorsal scales. Pupil round (B159)

Colouration: Variable.

  • Adult: Olive-grey, greenish, olive-brown or steel-grey body with dark blotches and sometimes light stripes. Usually black-bordered collar just behind head, collar usually yellow, sometimes white, orange, red. Eye orange.
  • Abdomen black, grey or white checkered. (B160).
  • Throat white or pale yellow (B160).
  • Britain, France, Switzerland, central Italy: Collar pale or absent, flanks usually have dark bars, back may have small spots in two alternate rows.
  • Collar orange, white or pinkish, usually divided in the middle, with black triangles/crescents on posterior border
  • Southern Italy, Sicily: Sides and back often have bars.
  • Iberia: Generally uniform, collar often absent.
  • Northern and north-eastern Europe: Collar well-developed yellow or orange. Body often has dark spots.
  • South-eastern Europe, northern Italy: Collar well developed, Body often with two pale stripes along length of body and often has spots, flanks often have bars.
  • Cyclades: May be almost entirely black, some are flecked with light yellow. Collar may not be obvious, Body commonly bears three rows of dark blotches.
  • Corsica, Sardinia: Collar usually weak. Body often has dark bars on either side, reaching close to mid-line or meeting at mid-line.
  • Black (melanistic): may occur throughout range; very rare in Britain.
  • Partial albinism may occur
  • (B159, B160).
  • Juvenile: Darker with markings less defined (B160).

Similar species and distinguishing features:

Distinguished from Natrix maura - Viperine snake and Natrix tessellata Dice snake by:

  • Lateral not upward-directed nostrils,
  • Broad rectangular internasal scales,
  • Typically seven upper labial scales, with third and fourth scales reaching eye, (Natrix maura also)Usually single pre-ocular scale
  • Two to four post-ocular scales
  • Usually 19 rows of dorsal scales
  • Not very strong keeling of dorsal scales, and keeling not always extending onto tail.
  • (B159).

Elaphe longissima Aesculapian snake may look similar when young. (B159).

Range and Habitat Range:

Europe, eastwards to western Russia, also to northern Europe and western Asia (B160)

  • Britain: widespread England and Wales (B160).
  • Not found in Ireland (B160).

Habitat:

  • Mainly found in damp areas.
  • In south of range: usually near water; may be found at up to 2400m.
  • Northern Europe: mainly lowland
  • Britain: open woodlands, hedgerows, marshy areas. Generally preferes areas near water but sometimes found in dry areas e.g. sandy heaths, chalky downs 
  • (B159, B160).
Further Information Activity:
  • Mainly diurnal.
  • Usually found in sunlit areas (e.g. sunny side of a valley); may bask on top of shrubs (B160).
  • Good climber, may be found in bushes and low trees although does not climb high up (B160).
  • Swim well, often searchs in water for food (B160).
  • May "play dead" when cornered (B160)
  • May void thick strong-smelling secretion from anal glands when handled, but rarely bite (B160).

Breeding:

  • Oestrous period several days B160
  • Mating usually in spring - April to May (B160)
  • Eggs laid: June to July; late June/ early July in southern England (B160)
  • Eggs often laid in warm places e.g. manure heaps; also in e.g. wall cavities, old tree trunks, earth of ploughed fields. Females burrows into heap and forma a chamber for the eggs. (B160)
  • Laying of whole clutch may take 10-12 hours (B160).
  • Several females may use same site (B160)
  • Matt white, 25-30mm x 16-20mm when laid; increase in size by several mm within a couple of weeks (B160)
  • Number of eggs/young: as few as 8-10 from young females, 30-40 usual for fully-grown females, and as many as 53 recorded (B160).
  • Hatch usually about two months (6-10 weeks) after laying; variation dependant on temperature and possibly on degree of development of embryos at time of egg laying; 6 weeks to hatching at 20-26C; mostly hatch late August/early September (B160)
  • Hatching: use well-developed egg tooth, make two or three long rents in shell, head emerges and several hours later juvenile emerges; egg tooth shed few hours later (B160).
  • Sexual maturity: males at about 50cm length i.e. autumn of third year (B160).

Food:

  • Frogs, newts, fish, tadpoles, toads, lizards, slow-worms, young birds, mice, voles, shrews (B160).
  • Juveniles may take worms, slugs and tadpoles (B160).

Feeding:

  • Hunt both on land and in water (B159, B160)

Predation: Badgers, hedgehogs, other mammals and birds (B160)

Organisations (UK Contacts):

Electronic Library (further reading):

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General Legislation:

Individual techniques:

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